System of transmission.



E. RIECKE.

SYSTEM OF TRANSMISSION. APPLIUATION FILED MAR. 20, 1908.

Patented June 15, 1909.

lnventfior Ernsif Rieckc;

UNITED STATES PATENT OFFICE.

ERNST RIECKE, OF BERLIN, GERMANY, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

s s'rnm or ramsmssron.

Specification of Letters Patent.

Patented June 15, 1909.

Application filed March 20, 1908. Serial No. 422,282.

' ject of the King of Prussia, residing at Bercation.

' of the fiy-wheel moto lin, Germany, have invented certain new and useful Improvements in Systems of Transmission, of which the following is a specifi- My invention relates to transmission-systems, and more particularly to such systems of transmission for mill orsimilar-motors which are subject to severe overloads, and has for its object the limiting of the power intake of the the like, which supplies the current for these motors.

Heretofore, in operating such systems, an excessive current is often supplied the motor generator when excessive overloads are thrown upon the mill motor which continue for such a period that the fly-Wheel slows down and can give up no more energy. By my invention the taking of such an excessive current by the motor of the fly-wheel motor-generator is prevented. This I accomplish by automatically decreasingthe voltage of motor of the fly-wheel motor-generator is excessively loaded due to the continuance of an overload'on the mill motor.

For a better understanding of my invention and the advantages possessed by it, reference may be had to the following description taken in connection with the accompanying drawing. I

The single figure shows diagrammatically a transmission system arranged in accordance with my invention in whlch the voltage of the generator is decreased by an automatic rheostat operated by the current flowing in the supply mains of the motor of the motor-generator when the driving motor is heavily overloaded. g

In the drawin A represents the armature .and a the field o a separately excited generator. This generator is driven by any suitable means as an induction motor B, supplied from the alternating current mains b. C represents a separate exciter WhlCh may consist of any suitable source of current as, for instance, of a small generator mounted on the shaft of the induction motor B, as

shown.

' D represents a fiy-wheel-which 1s coupled fly-wheel motor-generator or the generator when the V to the shaft of the a coupling 0.

E represents the armature of a motor supplied with current from the armature A of the generator, and 6 represents the field of the motor supplied with constant excitation from the exclter G.

F represents the control switch which is arranged to connect the generator field a to the exciter C to vary the current supplied to the generator field. It is arran ed so as to reverse the current through th1s field and to out either of the variable resistances G or H therein dependin upon the directlon of the current flowing t rough the field a.

generator A by means of I represents an automatic rheostat or slipregulator, which is arranged to cut resistance'into or out of the rotor circuit of the induction motor B. This sli -regulator consists of a slip-regulating or torque motor f supplied with current from a series tran former g which is inserted in the alternating current mains b, and of a water rheostat h, the plates of WlllCh are separated or brought together by the slight motion of the motor 7. This torque motor does not rotate but simply exerts a torque and is similar in its action to a solenoid. A similar device K operates to cut resistance into or out of the main generator field a. This device also consists of a motor lc, similar to the motor 7, su plied with current from a series trans ormer ,Z, and a water rheostat m which is normally shortcir'cuited. A switch 0 may also be inserted in the circuit of the motor 70.

In the drawing the switch F is shown in operative position for one direction of rotation. In this position it will be noticed that I a circuit is made from the exciter C, through the resistance G, control switch F, contact 1, water-rheostat m,- generator field a, contacts 2 and 3 to the other terminal of the exclter. By moving the switch F, more or less of the resistance G is placed in the field circult. Starting from the vertical or ofi' pos tion and moving the switch arm in either dlrection, the field circuit is closed through the whole of the resistance G or H, depending upon the direction of rotation desired of the motor E. If moved in the 0p osite direction from that shown in the rawing, the same circuit connections would have been motor generator is prevented from exceeding a certain amount by means of the slip-regulating device I. When the induction motor B is lightly loaded, the torque of the motor f and the weight go just balance the weight of the blades of the rheostat h. This rheostat is practically short-circuited in thisposition. As the load is increased the current taken by the motor B and the current transformed by the series-transformer. g is proportionally increased as is the torque of the motor f. As this torque increases the blades of the rheostat are separated in order to maintain the balance. This separation of the blades of the rheostat inserts resistance in the rotor circuit of the induction I motor B and tends to slow it down, thereby permitting the fly-wheel D to give up some of its stored energy. This condition maintains only as long as, during the period of maximum load, the slip-regulating device I continues to operate 'to decrease the speed of the induction motor B. When the slipregulator can decrease the speed no more, anexcessive load will be taken from the mains b.

To prevent the motor B from taking an excessive load from the mains when the motor E is heavily loaded and the slip regulator I can decrease the speed no more, the device K is provided, which operates in a similar manner to that of the slip regulator I to' cut resistance into the field a of the generator. The device K has its weight so proportioned that it will not operate until after the regulator I can decrease the speed of motor B no more. By this means, the potential of the generator A and consequently the speed of the motor E is decreased. The.

efliciency of the hoist or mill, the power input to the motor B and the power output of the generator A are afiected by this arrangement insuch a manner that the supply of current to the inotor B does not-exceed a certain amount.

' The device K may be cut out of the circuit by means of a switch 0, which at the same time short-circuits the transformer- Z, when an excessive overload on the motor E'is not to be feared.

Further, I desire it to be understood that my invention is not limited to the specific arrangement of circuits shown and de- -generator field in order to scribed, and I aim in the appended claims to cover all modifications which do not depart from the spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is,-

1. In a system of transmission, a source of current supplying a motor, a generator coupled to a 'fly-wheel, driven by said motor and supplying current to a second motor, means for decreasing the speed of the first mentioned motor when said second motor is excessively loaded, and means responsive to the load on the system for automatically insertin resistance in the generator field to limit t e power input to sald first mentioned motor.

2. In combination, a source of current supplying a motor, a enerator coupled to a fly-wheel and driven y said motor, means operated by the flow of current to said motor for decreasing its speed, and means for automatically inserting a resistance into the 7 limit the power input to said motor.

3. In combination, a source of current supplying a motor, a nerator coupled to a fly-wheel and driven y said motor, means operated by the flow of current to said motor for decreasing its speed, and means actuated by the flow of current to said motor for automatically inserting resistance into the generator field in order to limit the power input to said motor.

4:. In combination, a source of alternating current supplying an induction motor, said motor driving a separately excited generator coupled to a 'fiy-wheel, means operated by the flow of current to said motor for inserting resistance into the rotor circuit of said motor, and a second means actuated by the fiow of current to said motor for automatically limiting the power input to said motor.

5. In combination, a source of alternatin current supplying an induction motor, sai motor driving a separately excited generator coupled to a fly-wheel, means operated by the flow of current to said motor for inserting resistance into the rotor circuit of said motor, and a second means actuatedby the flow of current to said motor for automatically inserting resistance into the gen- 

